Field of the Invention
This invention relates to an automatic transmission failure determination apparatus, specifically to an apparatus for diagnosing failure of an electromagnetic valve (solenoid valve) of a hydraulic pressure supply circuit or the like in a double-clutch (twin-clutch) automatic transmission.
Description of Related Art
As an example of a double-clutch automatic transmission can be cited the one described in Patent Document 1 (Japanese Laid-Open Patent Application No. 2013-189993). The double-clutch automatic transmission set out in Patent Document 1 comprises input shafts connected through clutches to an engine or other power source mounted on a vehicle, an output shaft installed parallel to the input shafts, and a plurality of gear engaging mechanisms capable of establishing one among first to eighth speed gears by engaging one of the gears interposed between the input shaft and output shaft with the input shaft and the output shaft, and is equipped with a hydraulic pressure supply circuit having a line pressure-regulating valve for pressure-regulating hydraulic pressure discharged from an oil pump to line pressure, a plurality of pressure-regulating valves installed downstream of the line pressure-regulating valve, and a plurality of select valves for selectively supplying pressure-regulated hydraulic pressure to the gear engaging mechanisms, wherein the valves comprise electromagnetic valves.